Injection Mortar

ABSTRACT

Injection mortar for anchoring a fastener containing a chemical composition that can cure in a curing process, and means for initiating the curing process characterized in that the chemical composition cures when irradiated with electromagnetic radiation, the means for initiating the curing process is formed by a radiation source for electromagnetic radiation, and the radiation source is placed within the anchoring zone.

TECHNICAL FIELD

The invention relates to an injection mortar for fixing a fixing elementcomprising

-   (a) a chemical composition adapted to cure in a curing process; and-   (b) means for starting said curing process.

The injection mortar is also called a chemical screw anchor or shearconnector. Typical fixing elements are threaded rods, which are alsocalled anchor rods or armature bars. For fixing such fixing elements achemical composition is inserted into a bore hole in the form of, forexample, a cartridge. The bore hole then will form the injection mortarrange. The injection mortar is not sheared as with a shear connector buthardened. The chemical composition thereby connects to the surroundingwall material. The fixing element is usually inserted together with thechemical composition into the injection mortar range.

PRIOR ART

From DE 22 47 133 chemical screw anchors on the basis of reactive resinsare known for fixing fixing elements in concrete or brickwork. EP0703197 B1, EP 2357162 B1 and EP 1937745 B1 disclose two-componentsystems for use as chemical screw anchors. Such screw anchors have ahigh firmness. Known chemical screw anchors, however, require acomparatively long time for curing depending on the bore holetemperature. Accordingly, a long time is needed for achieving the finalfirmness. Further chemical screw anchors will cure within a short timeonly. Then only a limited amount of time remains for the application andadjustment correction. Furthermore, it is a problem that the processingtimes and the curing times are very much temperature dependent. Forexample, a system will cure within a duration of 15 minutes at atemperature of 40° C. and within 6 hours at a temperature of −1° C.

With known chemical screw anchors it is provided that both componentshave a very limited processing time (so-called can time) after mixing,which is strongly dependent on the bore hole temperature. The systemHilti HIT-HY-270 disclosed on the internet website www.hilti.de isadapted, for example, to be processed at temperatures below +10° C.within 10 minutes, at temperatures between 20 and 29° C. within onlyfour minutes and at temperatures at 40° C. within only one minute. Thecuring time is, again dependent on the temperature, between 6 hours at atemperature between −1 to 5° C. and 15 minutes at a temperature of +40°C. The enterprise Fischer offers quick systems on the basis ofcartridges on its internet website www.fischer.de, which can beactivated by screwing in a screw and which will cure within 2 minutes atroom temperature. A correction or re-adjustment is not possible anymorewith such systems already after a few seconds after opening thecartridge.

Curing of reactive resins with ultraviolet (UV-) radiation is known.UV-curing coatings are, for example, used in the automotive field and inthe printing industry in the form of UV curing colors. For themanufacturing of fiber composites UV-reactive resins are used. They arealso used as glues. The UV-curing is possible with only a comparativelysmall penetration depth. This is caused by the absorption of the resinsand the required photoinitiator. Depending on the wavelength the upperlimit is a little over one centimeter.

DE 10 2015 203 511 A1 discloses a fixing rod made of an endless fiberreinforced composite with a metal sleeve. The fixing rod is glued intothe bore hole in a brickwork. Fixing portions can be fixed at saidsleeve. It is explicitly provided that the fixing rod does not consistof metal. The printed document discloses that the fixing rod may beformed by glass fibers and that a one-component gluing system is usedwhich cures upon exposure to UV light.

DISCLOSURE OF THE INVENTION

It is an object of the invention to provide an injection mortar of theabove mentioned kind which has a particularly high stability and whichquickly cures at a freely selectable point in time.

According to the invention this object is achieved in that

-   (c) the chemical composition cures upon exposure to electromagnetic    radiation;-   (d) the means for starting said curing process is formed by a    radiation source for electromagnetic radiation; and-   (e) the radiation source is provided within the injection mortar    range.

A suitable composition is, in particular, a reactive resin which may bereinforced by glass fibers or glass powder. Examples for such UV-curingreactive resins are: acrylic resins, epoxides, unsaturated polyesterresins and vinyl ester resins.

A chemical composition is used with the present invention which is curedby radiation. The radiation source is directly positioned within therange of the injection mortar. Therefore, no large penetration depth forthe radiation is necessary. Accordingly, there is the possibility forre-adjustment after inserting the chemical composition and the anchor inthe bore hole. A particularly quick curing can be effected withswitched-on radiation source. If the chemical composition is protectedfrom radiation the materials can be stored for a long time withoutproblems.

With the invention new, very quick fixing systems can be developed forconstruction applications which have a very high storage stability. Suchdevelopment will put the construction industry in the position to fixfixings quicker, more reliably and furthermore mostly resistant toweather conditions, i.e. mainly temperature independent. The inventionenables that fixing elements can be fixed with UV-curing screw anchorsin a matter of seconds and be loaded within very short times which willhave positive effects for the construction progress. Furthermore, thefixing elements can be adjusted without hurry at complex and/ordifficult accessible positions.

The invention can be used, in particular, in the range of constructionand in construction chemistry. An extension of the application ranges tofurther branches, such as, for example, light weight construction forwind energy plants, planes, ships or trains are also possible.

Preferably, it is provided that the chemical composition cures uponexposure to the radiation from the radiation source with a wavelength inthe range between 300 nm and 420 nm, preferably in the range between 330and 420 nm and most preferably in the range between 360 and 420 nm. Suchradiation can be generated, for example, by light emitting diodes (LED).The longer the wavelength is the longer will be the penetration depth.The intensity normalized costs for LEDs are decreasing with longerwavelengths.

In a first variation of the invention, it is provided that the radiationsource entirely or partly remains in the injection mortar range. Inparticular the radiation source may comprise at least one light emittingdiode which is arranged in the injection mortar range and which hascontacts for the current supply and for the control outside theinjection mortar range. The rapid development towards ever moreefficient and less expensive UV-LEDs enables the use of the invention.In particular, UV-LEDs are suitable for the singular use which do notcomply with the specifications for long term use and which would bedisposed of otherwise as off-specification batches. It is not necessaryto carry out expensive optimizing of the operation, for exampleregarding the generated excess heat. The LED is switched on only oncefor a short time. It is not needed anymore thereafter.

Alternatively, it can be provided that the radiation source comprises atleast one optical fiber, which is arranged in the injection mortar rangeand which is fed with light from outside the injection mortar range. Theradiation source itself may then be used several times. Only a portionof the optical fiber remains in the injection mortar range.

In a third alternative modification of the invention, it is providedthat

-   (a) a sleeve is provided which is adapted to be inserted into the    injection mortar range;-   (b) the sleeve is provided with ranges, which are transparent for    the radiation of the radiation source; and-   (c) the radiation source is adapted to be retractably inserted into    the sleeve.

The sleeve may be fully transparent for the radiation. It may, however,also be provided that the sleeve is formed of an inexpensive plasticmaterial or metal which is opaque for the radiation and which isprovided with openings which are covered by transparent film or quartzglass layers or other UV-transparent materials. The film or quartz glasslayer prevents that the chemical composition enters the inside of thesleeve. The sleeve may have the form of a threaded sleeve. With such amodification the sleeve will fully protect the radiation source andenables its re-use. The radiation enters the range outside the sleevethrough the openings and thereby initiates the curing process. Withsufficiently small openings and sufficiently high viscosity of thechemical composition no accountable amount of resin will enter thesleeve and the covering of the windows may not be necessary.

In a particularly advantageous embodiment of the invention the chemicalcomposition is formed by a radiation-chemically curable 1-componentreactive resin. The reactive resin will then not require any furtherchemical treatment and can be easily stored and used as long as it isnot exposed to an activating radiation.

Modifications of the invention are subject matter of the subclaims. Anembodiment is described below in greater detail with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross section of a wall with three different injectionmortars.

DESCRIPTION OF THE EMBODIMENT

FIG. 1 shows a cross section of a wall 10 with three different injectionmortars. A fixing element 12 and 22 shall be fixed at the wall by meansof such injection mortar. In the present embodiments the fixing elementsare formed by a threaded rod of stainless steel, another metal or analloy. It is understood, however, that any other stable fixing element,such as a hook of stainless steel, another metal or an alloy or the likemay be fixed.

A bore hole 14 is drilled into the wall 10 for preparation and, ifnecessary, cleaned. Similar to known injection mortars a cartridge witha curable chemical composition 16 is inserted into the bore hole 14 orthe resin is directly injected by means of an injection or a cartridge.Contrary to known injection mortars, however, the chemical composition16 consists of glass fiber reinforced one-component reactive resin whichcures only upon exposure with UV light. The reactive resin will,therefore, not cure at first.

By screwing in of the fixing elements 12 or 22 the correspondingcartridge is opened. Its contents will enter into unevenness's andopenings of the wall 10 surrounding the bore hole 14. LEDs 24 areprovided in the bore hole. The LEDs 24 are contacted to the outside byconductors 20. When the fixing element 12 is correctly positioned andre-adjusted, if necessary, the LEDs 24 are switched on. A commonelectrical circuit and a current source are used for this purpose, whichare not illustrated here for easier representation.

The LEDs 24 emit radiation with a radiation maximum in the range 360 to420 nm. Upon exposure to light with such wavelength the reactive resinwill very quickly cure. Provided the right blend and the rightphotoinitiator are used it will quickly cure with any wavelength in theabove range. In the present embodiment 5 LEDs 24 sit around the coveredportion of the fixing element 12 in the injection mortar range. Uponswitching on, the LEDs 24 will illuminate the reactive resin whereby itcan quickly cure, i.e. within seconds. The LEDs 24 will continuouslyremain in the injection mortar. The cured reactive resin has a highfirmness similar to known injection mortars.

The fixing element 22 is also inserted into a cartridge with a curablechemical composition 16. No LEDs are provided therein, however, butoptical fibers 26. The optical fibers 26 have an adapted emissionprofile. The optical fibers 26 do not serve to receive forces. Theoptical fibers 26 extend in a longitudinal direction up to almost theend of the bore hole. The optical fibers 26 must be selected such thatthey emit light sideways in order to cure the entire resin.Alternatively, several optical fibers with different lengths can be usedwhich only emit light at the end. Light from a light source 28 iscoupled into the optical fiber. Here also LEDs are suitable as a lightsource 28. Since the light source 28 is outside the bore hole andoutside the injection mortar range, better, more expensive and largerlight sources 28 may be used with this embodiment. They can be re-used.While each optical fiber in the representation is provided with its ownlight source 28, it is obviously also possible to feed light from acommon light source 28 into several optical fibers. As with the use ofsunken LEDs 24 the curing can be initiated simply by switching on thelight source 28. After curing the light source 28 is separated andre-used if required. The optical fibers 26 are separated before the wallsurface of the wall 10. The ends remain in the injection mortar range.

The center bore hole 14 is provided with reactive resin which isprovided with a sleeve 30 in its inside. The sleeve 30 consists of metalwith high firmness. Openings 32 are provided in the sleeve 30. Atransparent film prevents the reactive resin 16 from entering the insideof the sleeve 30 through the openings 32. The sleeve 30 is provided withan inner thread adapted to have a fixing element screwed therein. Forcuring the optical fiber 34 or any other light source is inserted intothe inside of the sleeve 30 and the light source is switched on. Aftercuring the light source 34 can be removed from the sleeve 30 withoutdamage. Then the fixing element (not shown) can be screwed in.

1. Injection mortar for fixing a fixing element in an injection mortarrange in a bore hole comprising (a) a chemical composition adapted tocure in a curing process; and means for starting said curing process andwherein (b) said chemical composition cures upon exposure toelectromagnetic radiation; (c) said means for starting said curingprocess is formed by a radiation source for electromagnetic radiation;(d) said radiation source is configured to be placed within saidinjection mortar range when inserted into said bore hole; and (e)wherein said radiation source comprises at least one light emittingdiode which has contacts for a current supply and for a control outsidesaid injection mortar range, and wherein (i) said at least one lightemitting diode is arranged in said injection mortar range, and whereinsaid light emitting diode is configured to entirely or partly remain insaid injection mortar range, or (ii) a sleeve is provided surroundingsaid at least one light emitting diode, wherein said sleeve isconfigured to entirely or partly remain in said injection mortar rangeand wherein said sleeve and said radiation source are configured to havesaid radiation source retractably inserted into said sleeve so saidradiation source can be retracted from said sleeve when said sleeveremains in said injection mortar range.
 2. The injection mortar of claim1, and wherein said chemical composition is a reactive resin.
 3. Theinjection mortar of claim 2, and wherein said reactive resin isreinforced with glass fibers or glass powder.
 4. The injection mortar ofclaim 1, and wherein said chemical composition cures upon exposure tosaid radiation from said radiation source with a wavelength in a rangebetween 300 nm and 420 nm.
 5. The injection mortar of claim 1, andwherein said chemical composition cures upon exposure to said radiationfrom said radiation source with a wavelength in a range between 330 nmand 420 nm.
 6. The injection mortar of claim 1, and wherein saidchemical composition cures upon exposure to said radiation from saidradiation source with a wavelength in a range between 360 nm and 420 nm.7. The injection mortar of claim 1, and wherein said sleeve is providedwith ranges, which are transparent for said radiation of said radiationsource.
 8. The injection mortar of claim 7, and wherein said sleeve isformed by a plastic material or metal which is opaque for said radiationand which is provided with openings which are covered by a transparentfilm or glass layers.
 9. The injection mortar of claim 1, and whereinsaid sleeve has a form of a threaded sleeve.
 10. The injection mortar ofclaim 1, and wherein said chemical composition is formed by aradiation-chemically curable 1-component reactive resin.
 11. Use of areactive resin which is curable by exposure to UV radiation and of aradiation source as an injection mortar for fixing a fixing element,wherein said radiation source or a sleeve surrounding it, which isadapted to have said radiation source retractably inserted, remainsentirely or partly in said injection mortar range, and wherein saidradiation source is at least one light emitting diode or at least oneoptical fiber.
 12. Injection mortar for fixing a fixing element in aninjection mortar range in a bore hole comprising (a) a chemicalcomposition adapted to cure in a curing process; and means for startingsaid curing process and wherein (b) said chemical composition cures uponexposure to electromagnetic radiation; (c) said means for starting saidcuring process is formed by a radiation source for electromagneticradiation; (d) said radiation source is configured to be placed withinsaid injection mortar range when inserted into said bore hole; and (e)wherein said radiation source comprises at least one light emittingdiode which has contacts for a current supply and for a control outsidesaid injection mortar range, and wherein a sleeve is providedsurrounding said at least one light emitting diode, and wherein saidsleeve is configured to entirely or partly remain in said injectionmortar range and wherein said sleeve and said radiation source areconfigured to have said radiation source retractably inserted into saidsleeve so said radiation source can be retracted from said sleeve whensaid sleeve remains in said injection mortar range.
 13. The injectionmortar of claim 12, and wherein said chemical composition is a reactiveresin.
 14. The injection mortar of claim 13, and wherein said reactiveresin is reinforced with glass fibers or glass powder.
 15. The injectionmortar of claim 12, and wherein said chemical composition cures uponexposure to said radiation from said radiation source with a wavelengthin a range between 300 nm and 420 nm.
 16. The injection mortar of claim12, and wherein said chemical composition cures upon exposure to saidradiation from said radiation source with a wavelength in a rangebetween 330 nm and 420 nm.
 17. The injection mortar of claim 12, andwherein said sleeve is provided with ranges, which are transparent forsaid radiation of said radiation source.
 18. The injection mortar ofclaim 17, and wherein said sleeve is formed by a plastic material ormetal which is opaque for said radiation and which is provided withopenings which are covered by a transparent film or glass layers. 19.The injection mortar of claim 12, and wherein said sleeve has a form ofa threaded sleeve.
 20. The injection mortar of claim 12, and whereinsaid chemical composition is formed by a radiation-chemically curable1-component reactive resin.